Honda Civic Owner's Manual page 75

IMA Battery Level Gauge
BATTERY LEVEL GAUGE
This gauge shows you the state of
charge of the battery for the
Integrated Motor Assist (IMA). This
battery is recharged by the IMA
motor, and discharged by the IMA
when it is assisting the engine with
powering the vehicle.
The gauge reading may drop near
the bottom under driving conditions
that require IMA motor assistance
for a long time, such as prolonged
acceleration or climbing a long hill.
The IMA motor will recharge the
battery as you continue driving.
If the battery is mostly discharged,
the Auto Idle Stop function is
disabled (see page 170 ).
The battery level gauge does not
read the battery level directly. It
calculates the level by continuously
measuring the current flow, voltage,
and temperature.
Since the level is not read directly,
small sensing errors can, over time,
cause the gauge to read higher than
the actual battery level. The system
will then perform a correction, and
the battery level gauge reading will
drop suddenly. When this happens,
IMA assist and Auto Idle Stop are
disabled until the IMA battery is
sufficiently recharged by normal
driving. This should take only a few
minutes.
Gauges
This correction of the battery level
gauge is normal and does not
indicate a problem. If the IMA
battery develops a problem or
becomes deteriorated, the IMA
system indicator will come on. If this
happens, have the vehicle checked
by your dealer as soon as possible.
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